@book{4431,
	author = {HAYWOOD, H.C. and SWITZKY, H.N.},
	title = {INTRINSIC MOTIVATION AND BEHAVIOR EFFECTIVENESS IN RETARDED PERSONS EN: INTERNATIONAL REVIEW OF RESEARCH IN MENTAL RETARDATION. VOLUME 14},
	publisher = {ACADEMIC PRESS},
	year = {1986},
	address = {Londres}
}